Athletic implement



March 25, 1941. M. B. REACH ATHLETIC IMPLEMENTS' Filed Feb. 27', 1939IIIIIIIIIIIIIIII IIIIIIIIIIIIIIII Patented Mar. 25, 1941 UNITED STATES'PATENT OFFICE 2,236,414A v y ATHLETIC IMPLEMENT I Milton B. Reach,Springfield, Mass. v Application February 27, 1939, Serial No. 258,788

13 Claims.

The invention relates to golf clubs or the like and more particularly toimprovements in the construction of the shaft portion thereof employinga tubular metal shaft.

An object of the invention is to provide a construction of golf clubshaft which is designed to provide for requisite torsion and control oftorsion, particularly at the grip end of the shaft, While maintainingstrength and serviceability, and without interfering with proper weightbalance of the club.

Other objects will appear hereinafter, the invention consisting in thefeatures, combination, and arrangement of parts and the procedural stepsas hereinafter described, and as particularly pointed out in the claims.

In the drawing Figure 1 is a longitudinal sectional view of a portion ofa metal golf shaft constructed for carrying out the invention, takensubstantially on line l-I of Fig. 3. Y

Fig. 2 is anl elevation of the shaft portion.

Fig. 3 is a cross sectional view of the 'shaft substantially on the line3-3 of Fig. 2.

Fig. lis a longitudinal sectional view of a completed grip portion ofthe shaft embodying the invention.

Fig. 5 is a cross-sectional View substantially on the line 5-5 of Fig.4.

Fig. 6 is a longitudinal sectional view of a modified construction, andFig. 7 is a section thereof substantially on the line 'I-'l of Fig. 6.

Fig. 8 is a longitudinal sectional View of a further modication, VandFig. l 9 is a section thereof substantially on the line 9 9 of Fig. 8.

Since the advent of the steel shaft, which has practically completelyreplaced the former hickory shaft, manufacturers and designers of golfclubs have sought to introduce into the steel shaft the torsionalqualities of hickory. In all other respects the steel shaft has provenitself superior to hickory through its standardization andcontrollability of weight and stiffness.

For twenty-live years the problem of produce ing a satisfactorytorsional quality in steel has not been solved because of the need ofcertain corollary attributes.

Weight is an important factor; strength is another important factor;proper controllability of torsion, another important factor.

A proper theory of golf club construction demands that the center ofpercussion be maintained as low on the shaft, that is, as near the head,as possible in order to obtain the maximum flowof power with'a minimumof total weight (C1. 27s-s0) and to provide the least amount of jarunder impact. It is therefore desirable to have the grip end of the clubrelatively light for its size, and as much weight as can be convenientlyhandled located in the head end of the club. Any torsional element thatsubstantially increases the weight at the grip end of the club would notbe popular because the virtue of the torsion would be more than offsetby faulty balance.

Any torsioning device that affected the serviceability also would not beacceptable.

One of the most popular conceptions intended to produce torsion orresilient twisting ability has been through the medium of grooves inythe shaftanother has been through the medium of slots and holes.

With respect to the former it may be definitely stated that any groovingoperation that will actually produce torsion or twisting ability undertorsional stress or torque cannot practically be applied to the presentlight weight construction of a steel golf shaft. And any arrangement ofperforations applied to the present thinwall golf shaft has weakened theshaft beyond its limit of playability.-

The accumulative elfects of the vibrations under impact and thedistortions of impact focus at the weak points, and the shaft gives way.

Under-the proposed novel assembly described herewith, atorsioning shafthas been produced that has successfully met the requirements ofplayability and service.

At the grip end of the club for a distance of l2 or 14 inches,approximately, I preferably form groovesl 2 on opposite sides of theshaft l of substantially a U-shaped formation in cross-section. Thesegrooves in themselves will not produce the requisite torsion or abilityto twist. Along the base of each groove I preferably provide a series ofslots 3 and a corresponding series of slots in the groove opposite onthe opposite. side, the slots desirably being out of registration witheach other, that is, maintaining a staggered relationship. In this stageof manufacture, the shaft now has torsioning or twisting ability, butunder the stresses of impact and the effects of vibration it has beenfound that the weakened parts tend to break down. To overcome this faultand; provide the necessary attributes, I may preferably fit into theshaft a suitable mandrel which contacts its entire walls. I desirablythen coat the outer walls of the shaft and the edges of the slots with aproduct known asr thermoprene, which has the quality of bonding steeland rubber together in a vulcanizing proc'- ess. I may then desirablylay in the grooves the required volume of raw rubber to completely fillthe orifices and allow for some excess iow. Thereafter this part of theshaft is placed in a suitable mold, heat is applied, and under this heatand pressure the rubber element flows and is cured and completely bondedwithin the grooves and slots, as seen in Figs. 4 and 5. The rubberstrips, besides furnishing backing or sustaining means for the groovedand slotted part of the shaft, also provide means by which the grip maybe attached to the shaft. The excess rubber in the strips, in flowing inthe molding operation, may form in a thin film around the shaft, asinFigs. 4 and 5, since it is desirable to provide enough excess rubberpacked in the groove to insure that all walls of the grooves and slotsare thoroughly contacted by the rubber. This lm of rubber may be buffedoff after the molding, if desired. Preferably, however, the thin lm ofrubber around the shaft is retained and provides a good anchorage forthe adhesion of the molded cork foundation.

This rubber 4 acts as a barricade or baffle to the vibrations of theshaft causing them to dissipate under the hand, and beingnon-compressible, it sets up a proper resistance and control to anyclosures and distortions of the weakened part, so that under impact theymay not be overstressed or strained and a proper degree ofserviceability is attained.

A modification of the assembly may desirably be made as in Figs. 6 and 7by cutting a suitable number of slots 3 preferably in a staggeredrelation through the walls of the shaft, a lining tube of rubber 4aplaced within the shaft, a mandrel (not shown) supporting the liningtube, a mold placed on the outside of the shaft, the surfaces of theshaft having been previously treated with thermoprene or the like, heatapplied, the molding pressure forcing the rubber to flow over the insideofthe shaft through the slots to the outside surface, bonding itself inthe form of an inner lining 4a extending through the slots andpreventing harmful collapse of the slots under the stresses of impact. yf

The usual foundation 5, as of cork, and grip covering 6, as of leather,may be applied, as well as an end plug or cap 1 of any suitableconstruction, which is shown applied in Fig. 4.

I prefer the rst described method, but do not limit myself to thatparticular form of assembly, the basic idea being to fill and supportthe torsioning elements or openings in the shaft with a plastic,yielding, but relatively non-compressible material that will impose aproper restraint on the action of the torsioning elements or openings,and free them from the dangers of weakening under the forces of impact.

Another alternative way of making as indicated in Figs. 8 and 9 would beto form a grip 4b of a suitable rubber compound, slot or perforate theshaft to its required degree as at 3, fill theinterior of the shaft witha removable steel man-- drei, provide an excess volume of rubber in thegrip mold in which the shaft would be inserted, and under pressure theexcess rubber in the walls of the grip would be caused to ow inwardlythrough the slots until it met the barricade of the mandrel, when itwould under pressure completely fill the slots and bond itself theretothrough a prior treatment of thermoprene.

While itis` not desired to restrict the invention to thermo'prene as thebonding material used to bond the rubber to the metal shaft, thisproduct has been found to be a desirable bonding material. Thermoprenemaybe described as a product of the general type of that produced by thereaction of rubber with an agent selected froml the group consisting ofsulfuric acid, sulfonic acids, and sulfonyl chlorides. The presentinvention, however, is not restricted to the use of this particularbonding material.

Alternatively or in addition to attaching the rubber or othernon-compressible plastic substance to the shaft by means of a bondingmaterial, such as thermoprene, the invention contemplates any suitablemeans or method for bonding the plastic or rubber material to the metalshaft, which may desirably be done by brass plating the surfaces of themetal and attaching the rubber material to the brass plating. Or therubber material may be vulcanized to a brass strip and the brass may beattached to the steel Wall of the groove by brazing or otherwise.

The invention also contemplates attaching the rubber or plastic materialby a mechanical fit or interlock within the perforations in the metalshaft, without the use of bonding material. This may desirably be doneaccording to the present invention by a mechanical molding job in whichthe several perforations or orifices in the shaft may be lled underpressure and a sufficiently close contact against the walls of theorifices maintained through a mechanical fit to substantially restrainand prevent any excess distortion of these orifices under the force ofimpact and torsion.

The yieldable reinforcing material may desirably be rubber or rubbercompounds, or rubbery compositions especially adapted to absorb shock,although any suitable plastic material may be used.

The perforations are desirably of slotted form and. may be cut in thebottom of the grooves, as in Figs. 1 to 5, by means of a cutter of anysuitable diameter, say two inches, and in any suitable number, say'fourin each groove, on the opposite sides of the grip end of the shaft. Or,as in Figs. 6 to 9, the slots may be cut directly in the wall, withoutgrooves.

It will be noticed that in the form of the invention shown in Figs. 1 to5, the walls of the groove desirably flare outwardly and that theopenings or slots are preferably of less width than the groove. In theform of the invention shown in Figs. 6 and 7, the inner portion 4a ofrubber or other material serves to lock the reinforcing yieldablematerial in place acting as an internal key for this purpose. l

In all forms of the invention slots or openings are provided in whichrubber or other yieldable reinforcing material is disposed.

This rubber `allows the twisting action of the shaft to take place. Itprevents the slotted shaft from collapsing under the torsional strain,which, if the rubber strip were not used, would deform by the approachof the opposite edges of the slot towards each other. The rubber beingnoncom pressible, will sustain the slotted part of the tube fromcollapsing. It will also have a renitent or resilient reaction whichwill aid in effecting the restoration of `the shaft to its originalcondition after it has performed its torsional action.

The'portions of the rubber member passing into and through the slotswill serve as anchor' taining means for the slotted part of the shaft,also provide means by which the grip may be attached to the shaft.

It will be understood that where a feature, or features, shown inconnection With one form are capable of use with another form of theinvention, they are to be considered as disclosed in connection withsaid other form.

The invention is not limited to golf club shafts, but is applicable tothe shaft or handle of any athletic implement, such, for example, as thetubular metal shaft or handle of a racquet, for tennis or badminton orthe like.

I claim:

1. A tubular athletic implement shaft of thin metal having openings inits Wall communicating with the interior of the tube, said openingsbeing spaced apart, and yieldable resilient reinforcing materialextending into said openings, said yieldable resilient reinforcingmaterial overlying and engaging the thin metal edges forming theopenings and resiliently supporting the said edges against excessivedistortion as the shaft twists or torsions in use.

2. An athletic implement shaft according to claim 1 in which saidyieldable reinforcing material comprises rubber material, said rubbermaterial being bonded to the metal of the shaft.

3. An athletic implement shaft of thin tubular metal grooved in alengthwise direction thereof and having at intervals openings in thebottom wall of said groove communicating with the interior of the tube,and a strip of rubber or the like in the groove and extending into theopenings and united with the shaft within the groove and openings.

4. An athletic implement shaft according to claim 3 in which theopenings at the bottom of the groove are in the form of slots.

5. An athletic implement shaft according to claim 3 in which the grip isattached to the said rubber strip, or strips.

6. An athletic implement shaft according to claim 1 in which saidyieldable reinforcing material comprises rubber material, a lining tubeof rubber material within the shaft and integral with the rubbermaterial in the openings, said rubber material being bonded to theportions of the metal shaft with which it contacts.

'7. An athletic implement shaft according to claim 3 in which groovesare provided spaced around the shaft, the strips of rubber in thegrooves and openings having a thin lm of excess rubber lntegral withsaid strips and extending around the shaft.

8. An athletic implement shaft according to claim 1 in which saidyieldable resilient reinforcing material comprises rubber material andis bonded to the metal edges of said openings, and rubber materialextending over a surface portion of the shaft adjoining said openingsand bonded thereto and integral with the rubber material in theopenings.

9. A tubular athletic implement shaft of thin metal grooved in alengthwise direction thereof, and having an opening in the bottom wallof said groove communicating with the interior of the tube, and aquantity of yieldable resilient reinforcing material in said groovebonded to the Walls thereof and extending into the opening, saidyieldable resilient reinforcing material engaging the edges forming theopening and resiliently supporting the said edges against excessivedistortion as the shaft twists or torsions in use.

10. A tubular `athletic implement shaft of thin metal having openingsthrough its wall and having a resilient filler of rubber like charactermoulded in said openings and reinforced in its position within saidopenings by a bonded union with the adjacent metal surfaces of theshaft, and providing a controlling cushion for the metal of the shaftagainst fatigue and breaking strain in the magnified torsioning ortwisting of the shaft provided by said openings.

11. A tubular athletic implement shaft of metal having relatively thinwalls with U shaped channels formed therein and extending lengthwisethereof, open slots out through the bottom of the U channel in spacedrelationand resilient material disposed in the channel in a bonded unionwith the walls thereof to prevent excess or harmful movement in thechannel and open slots during the torsional winding andunwinding thattakes place at impact and following impact.

12. A thin walled tubular metal athletic implement shaft having meanscomprising spaced apart openings through the thin metal Wall of theshaft to increase torsional action under impact, and resilient meansassoci-ated with said torsion increasing'means to resiliently limit andcontrol the torsional winding and unwinding action, said resilientcontrolling means comprising rubber material extending into saidopenings and in bonded relation with the metal surfaces forming andsurrounding said openings.

13. A thin walled tubular metal athletic implement shaft having meanscomprising openings therein to increase torsional action under impact,said torsional means also comprising grooves extending lengthwise of theshaft and having said vopenings in the bottoms of the grooves, andresilient means associated with said torsion increasing means toresiliently limit and control the torsional winding and unwindingaction, said resilient .controlling means comprising'rubber materialdisposed in said grooves and bonded to the metal surfaces thereof.

MILTON B. REACH.

